Heat the oil in a large saucepan and fry (saute) the onion, garlic,
pepper, carrot and celery for about 5 minutes until soft but not brown.
Add the rice and stir until hot and shining. Stir in the tomatoes,
followed by the paprika to taste, and the sugar. Stir in the stock, bring
to the boil, then simmer for about 10 minutes until the rice is tender and
most of the liquid has been absorbed. If there is still too much liquid,
boil for a minute or two to evaporate. Stir in the sausage and heat
through, then season to taste and serve.